Various types of cosmetic applicators are known in the art. Brushes for applying mascara to eyelashes, for example, generally include a stem having a first end attached to a handle. An applicator head, such as brush bristles, are coupled to a second end of the stem. In use, the brush head loaded with mascara is applied to the eyelashes.
Mascaras come in a variety of forms including cakes or blocks, creams, gels, semi-solids, and low viscosity liquids. Cake mascaras were originally the most popular form consisting of at least 50% soap with the pigment mixed in with the soap cakes. With a wet brush, the mascara could be lathered and then applied to the lashes resulting in a satisfactory smooth application, but with a thin cosmetic coating on the individual lashes. The primary drawback was that the film on the lashes was very water soluble and prone to smudging and running on the skin around the perimeter of the eye. As a resolution, waxes were incorporated into mascara compositions thereby improving their water-resistant properties. Unfortunately, the smoothness of the application was adversely affected. That is, as the viscosity of the mascara formulation increased, it became increasingly harder to apply, messier, and yielded less separation of the lashes.
With the advent of mascara applicators a means for expanding formulation options for mascaras came into existence. Creams, for example, combined with a twisted metal wire brush or wand application provided a convenient use and composition that enabled the incorporation of film formers to improve the rubbing resistance and flexibility of mascara films. This also allowed a convenient implement to separate and build the lashes. Today, there are several types of mascara formulations including anhydrous, water-in-oil emulsions, oil-in-water emulsions, and water-based mascaras that contain little or no oil phase. The emulsions, previously mentioned, may also be multiple emulsions for example, but not limited to water-in-oil-in-water emulsion. Many mascaras are water-based emulsions and contain emulsified waxes and polymers usually with pigments dispersed into the water phase. The water provides curling and application properties, while the waxes and polymers create the transfer resistant end mascara film on the lash that is colored by the pigments. Anhydrous and water-in-oil mascaras are generally referred to as waterproof mascaras, as they have superior transfer resistance, especially to water. Their high content of hydrophobic materials creates a film which contains very little materials that allow water to break up the film and make it wear away. In the case of the water-in-oil mascaras, the internal droplets of water can deliver water-soluble/dispersible materials that would otherwise not be able to be incorporated into an oily phase. The water-based mascaras are typically gelled water with a polymer to create deposition and hold of the lashes. These mascaras usually do not have colorants, although colorants can be added in.
Consumers expect particular properties from their mascara products such as adhesion to the lashes, lengthening/curling of the lashes, lack of smudging or flaking, thick lashes, and good separation of clumps of lashes. Particularly, the desire is for long, luscious, full, soft, and separated lashes. Mascaras generally distribute a smooth and relatively thin (coating thickness) film over the eyelashes producing a satisfactory array of reasonably separated lashes that are darker and thicker than bare lashes, making the eyes more noticeably beautiful. It is well understood that some lash clumping will naturally occur since lashes are arranged in both rows and columns above and below one's eye. Therefore, “separated” lashes are not necessarily envisioning every lash as a single entity. Mascara that is deemed by a user to separate well will leave more clumps of lashes than mascara that is deemed not to separate lashes well. Typically, the deposition of mascara has a coating that is 5-15 microns thick. Many “volumizing” mascaras, however, are messy and clumpy and tend to clump too many lashes together in a thick, less separated look which gives the look of fewer lashes.
Conventional mascara brushes typically require manipulation of the handle or other member, and often require repeated passes of the brush across the eyelash, to completely and uniformly coat each eyelash with mascara while maintaining or promoting separation of the eyelashes from one another. To coat the entire eyelash, for example, a user may move the brush in a vertical direction to ensure that the entire eyelash is covered. In addition, a user may rotate the brush to place different portions of the brush head in contact with the eyelash, depending on the desired amount of mascara to be applied to the eyelashes. Still further, a user may also reciprocate the brush in a horizontal direction to promote separation of the eyelashes and/or to ensure better coverage of the eyelashes. Consequently, a user must provide the motive force for applying the brush to the eyelashes and must have sufficient dexterity to manipulate the brush as needed to cover the eyelashes in a satisfactory manner. In addition, mascara application with conventional brushes requires several brush passes and therefore is inefficient.
More recently, rotating mascara brushes have been proposed in which a stem of the brush is supported for rotational movement with respect to the handle. The force for rotating the stem and attached brush head may be either manual, such as for the brushes described in U.S. Pat. No. 6,145,514 to Clay and U.S. Pat. No. 5,937,871 to Clay, or may be electrically driven, such as the brush described in U.S. Pat. No. 6,565,276 to Diaz. While these rotating stem brushes eliminate the need for a user to roll the handle during application of mascara, they do not optimally coat and separate the eyelashes. Furthermore, these brushes are limited to simple, unidirectional rotation of the brush head, and therefore are not capable of performing certain, potentially more complex, application techniques.
In addition, various types of applicators have been designed which are adapted to impart different types of eyelash effects. For example, a first brush design may promote separation of eyelashes while a second brush design promotes volume or coverage of the eyelashes. Consequently, a user must use two separate brushes or, if a single brush head is provided with both types of brush designs, the user must reposition the handle to use both sides.